如何在dp值中设置Layoutparams的高度/宽度？

Question

I tried setting height/width manually in button but it didn't work. Then implemented Layoutparams. But size shows small and not getting required dp value.

XML

 <Button
    android:id="@+id/itemButton"
    android:layout_width="88dp"
    android:layout_height="88dp"
    android:layout_marginRight="5dp"
    android:layout_marginBottom="5dp"
    android:background="#5e5789"
    android:gravity="bottom"
    android:padding="10dp"
    android:text=""
    android:textColor="#FFF"
    android:textSize="10sp" />

Constructor:

  public Item (int id, String name, String backgroundColor, String textColor, int width, int height){
    this.id = id;
    this.name = name;
    this.backgroundColor = backgroundColor;
    this.textColor = textColor;
    this.width = width;
    this.height = height;

}

Adapter:

@Override public void onBindViewHolder(final ViewHolder holder, int position) {
    final Item item = items.get(position);
    holder.itemView.setTag(item);
    holder.itemButton.setText(item.getName());
    holder.itemButton.setTextColor(Color.parseColor(item.getTextColor()));
    holder.itemButton.setBackgroundColor(Color.parseColor(item.getBackgroundColor()));
    ViewGroup.LayoutParams params = holder.itemButton.getLayoutParams();
    params.width = item.getWidth();
    params.height = item.getHeight();
    holder.itemButton.setLayoutParams(params);

}

Answer 1

When you specify values programmatically in the LayoutParams , those values are expected to be pixels.

To convert between pixels and dp you have to multiply by the current density factor. That value is in the DisplayMetrics , that you can access from a Context :

float pixels =  dp * context.getResources().getDisplayMetrics().density;

So in your case you could do:

.
.
float factor = holder.itemView.getContext().getResources().getDisplayMetrics().density;
params.width = (int)(item.getWidth() * factor);
params.height = (int)(item.getHeight() * factor);
.
.

Answer 2

  ViewGroup.LayoutParams params = ListView.getLayoutParams();
        params.height = (int) (50 * customsDebts.size() * (getResources().getDisplayMetrics().density));
        params.width = ViewGroup.LayoutParams.MATCH_PARENT;
        ListView.setLayoutParams(params);

Answer 3

I believe you should be using a dp value defined in dimens along with getDimensionPixelSize . In a custom view, the Kotlin implementation would look like:

val layoutParams = layoutParams
val width = context.resources.getDimensionPixelSize(R.dimen.width_in_dp)
layoutParams.width = width

Answer 4

Option 1: Use dimens.xml

view.updateLayoutParams {
    width = resources.getDimensionPixelSize(R.dimen.my_width)
    height = resources.getDimensionPixelSize(R.dimen.my_height)
}

Option 2: Dispense with dimens.xml

/** Converts dp to pixel. */
val Int.px get() = (this * Resources.getSystem().displayMetrics.density).toInt()

view.updateLayoutParams {
    width = 100.px
    height = 100.px
}